Outdoor unit, air-conditioning apparatus, and method for manufacturing outdoor units

ABSTRACT

Heat exchanger assemblies included in an outdoor unit each include fins each having notches provided without fin collars or notches provided with fin collars that are shorter than stacking intervals between the fins. At least some of the stacking intervals between the fins in a facing surface are larger than the stacking intervals between the fins in surfaces excluding the facing surface.

TECHNICAL FIELD

The present invention relates to an outdoor unit and an air-conditioningapparatus including the outdoor unit.

BACKGROUND ART

Known industrial-use air-conditioning apparatuses intended for officebuildings, factories, and so forth include those having relatively highpower with outdoor units thereof each configured to exhaust air from twopositions in an upper portion in external view. A known outdoor unithaving such a configuration includes, in its housing, devices such as aheat exchanger assembly, a compressor, pipe components, and so forth,with two propeller fans and two bell mouths that guide the flow of airprovided in the upper portion of the housing (see Patent Literature 1,for example). In such an outdoor unit, when outdoor air sucked into thehousing by an effect of the propeller fans is made to flow through theheat exchanger assembly, the outdoor air exchanges heat with arefrigerant, and the resulting air is guided by the bell mouths and isexhausted from the upper portion of the housing.

In general, the heat exchanger assembly included in such an outdoor unithas a two-layer configuration including two heat exchangers. Many of theknown heat exchangers employ a plate fin-tube structure obtained asfollows: a plurality of strip-like aluminum fins each having circularholes are stacked, a plurality of copper or aluminum heat transfer tubeseach having a circular cross-sectional shape are inserted into the finsin a direction substantially vertical to the fins, and the bores of theheat transfer tubes are expanded by using a hydraulic or mechanical tubeexpander, whereby the closeness between the fins and the heat transfertubes that is required for providing heat transferability of the heatexchanger is guaranteed (see Patent Literature 2, for example).

The edges of the circular holes provided in each of the fins are burredand thus form cylindrical collars so that the area of the fin that is inclose contact with each of the heat transfer tubes is increased.Furthermore, flat portions of the fin between the circular holes haveslits that improve the heat exchangeability with draft air. In adisclosed technique (see Patent Literature 3, for example), the circularholes, the collars, and the slits of the fin are sequentially formed asfollows: a progressive die including a plurality of manufacturing stepsections is placed on a pressing machine, and the pressing machine isoperated consecutively while a strip-like aluminum hoop is fed thereto.

In a typical method of manufacturing a plate fin-tube heat exchanger,after pressing is performed, a desired number of fins obtained bycutting and each having a desired strip length are sequentially stackedin a collar section. Subsequently, a plurality of long heat transfertubes called hair pins and each including a U-shaped portion areinserted into the fins, and the tubes are expanded. Since the stackingof the fins and the insertion of the heat transfer tubes are performedwith reference to collars, the fins are consequently stacked and fixedat regular intervals corresponding to the height of the collars (seePatent Literature 4, for example).

In such a plate fin-tube heat exchanger, a plurality of heat transfertubes are brazed to U-bends, which are heat transfer tubes for pipeconnection each having a circular cross-sectional shape and being bentin a U shape at an end, and to other components such as a distributor,whereby a continuous refrigerant passage that is folded many times whilepassing through the stack of fins is provided.

In another disclosed plate fin-tube heat exchanger (see PatentLiterature 5, for example), a stack of fins through which heat transfertubes extend is bent in an L shape a plurality of times (twice, forexample). In such a plate fin-tube heat exchanger, the stack of fins isbent a plurality of times. Ultimately, the plate fin-tube heat exchangeris used as a substantially U-shaped heat exchanger in which the fins arestacked and the heat transfer tubes extending therethrough extend in adirection of a contour line (see Patent Literature 5, for example). Inthe substantially U-shaped heat exchanger having three outer surfacesobtained as a result of bending the stack of fins, all of the fins areat regular intervals corresponding to the height of fin collars anddetermined in a state prior to bending.

In addition, in view of recent circumstances concerning enthusiasticdiscussions about energy problems and so forth, highly competitiveenergy-saving and cost-reduction strategies are underway. Accordingly,various measures have been sought for further improvements in the shape,the pitch (the stacking intervals between the fins and the intervalsbetween adjacent heat transfer tubes), the materials (the material ofthe fins and the material of the heat transfer tubes), and other factorsof the heat transfer tubes and the fins. Other measures have also beenproposed in which the pitch of the fins is changed in accordance withthe internal configuration of the outdoor unit (see Patent Literature 6to 8, for example).

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Unexamined Patent Application    Publication No. 2008-138951 (FIGS. 1 to 3 and others)-   Patent Literature 2: Japanese Examined Patent Application    Publication No. 58-13249 (FIGS. 1 to 3 and others)-   Patent Literature 3: Japanese Examined Patent Application    Publication No. 58-9358 (FIGS. 1 to 5 and others)-   Patent Literature 4: Japanese Examined Patent Application    Publication No. 3-80571 (FIGS. 1 and 2 and others)-   Patent Literature 5: Japanese Patent No. 4417620 (FIG. 20 and    others)-   Patent Literature 6: Japanese Unexamined Patent Application    Publication No. 63-233296 (FIGS. 1 and 2 and others)-   Patent Literature 7: Japanese Unexamined Patent Application    Publication No. 2004-245531 (FIGS. 1 and 2 and others)-   Patent Literature 8: Japanese Unexamined Patent Application    Publication No. 2008-8541 (FIG. 3 and others)

SUMMARY OF INVENTION Technical Problem

As described above, in an air-conditioning apparatus employing a heatexchanger that is manufactured by a method including stacking of finshaving circular holes, insertion of circular tubes, and expansion of thetubes, the pitch of the fins is a constant value determined by theheight of collars formed by burring. Therefore, in such a knownair-conditioning apparatus, it is difficult to change the pitch of thefins, for performance improvement, in accordance with the internalconfiguration of an outdoor unit.

Particularly, in an air-conditioning apparatus including a plurality ofsubstantially U-shaped heat exchangers that are arranged side by side,the cross-sectional area of openings as air inlets provided betweensurfaces of substantially U-shaped heat exchangers that are adjacent toeach other is smaller than the cross-sectional area of openings as airinlets provided in the other four surfaces (two surfaces of each of twoheat exchangers excluding the foregoing surfaces that are adjacent toeach other), and the wind speed is therefore lower in the surfaces thatare adjacent to each other. To improve cost performance withconsideration for such a fact, a measure of changing the stackingintervals between the fins in accordance with the position (the positionin the outdoor unit) may be taken. Practically, however, it is difficultto change the pitch of the fins in accordance with the internalconfiguration of the outdoor unit, as described above.

In other proposed configurations, the pitch of the fins is changed insome portions by dividing the heat exchanger, by changing the settingfor the height of the collars, and by using other techniques. In such acase, different kinds of progressive dies for forming fins need to beprepared, or a die including a mechanism that can alone change thesetting for the height of burring needs to be prepared. Moreover,troublesome assembling work including setting for different groups offins is required. Therefore, the die may become complicated or large, orthe pressing machine may become large. Consequently, the costs of thedie, the pressing machine, and the assembling work may become too highto realize any of the above configurations. Moreover, the variations inthe height of collars that are determinable by the die are limited totwo to three at most because the size of the die is limited. Such alimitation also makes the realization of the above configurations moredifficult.

To avoid the above problems, another measure may be taken in which theheight of the collars is made smaller than the stacking intervalsbetween the fins, and the fins are not stacked with reference to theheight of the collars. In such a case, however, each heat transfer tubecannot be inserted into a group of fins that are in a stacked state,that is, the fins need to be fitted one by one onto the heat transfertube while each of the fins is moved toward the distal side of the tubeby a long stroke corresponding to the length of the heat transfer tube,leading to significantly troublesome work. This shows that changing thepitch of the fins is impractically difficult.

The present invention is to solve the above problems and to provide anair-conditioning apparatus in which the stacking pitch of fins isreadily changeable.

Solution to Problem

An outdoor unit according to the present invention includes a housing,at least two plate fin-tube heat exchanger assemblies arranged side byside in the housing and each being bent in an inward direction of thehousing such that the heat exchanger assembly has a facing surface thatfaces a surface of another heat exchanger assembly in the housing, and afan provided above the housing and causes air taken in from surfaces ofthe housing to be exhausted from an upper portion of the housing. Eachof the heat exchanger assemblies includes fins each having notchesprovided without fin collars or notches provided with fin collars thatare shorter than stacking intervals between the fins. At least some ofthe stacking intervals between the fins in a portion forming the facingsurface are larger than the stacking intervals between the fins inportions forming surfaces excluding the facing surface.

An air-conditioning apparatus according to the present inventionincludes the above outdoor unit and an indoor unit connected to theoutdoor unit.

Advantageous Effects of Invention

In the outdoor unit according to the present invention, since the finscan be distributed more effectively than in the known art, the heatexchanging efficiency is improved from the viewpoint of costperformance. Thus, energy saving and cost reduction are realized.

In the air-conditioning apparatus according to the present invention,since the above outdoor unit is employed, the heat exchanging efficiencyis improved from the viewpoint of cost performance. Thus, energy savingand cost reduction are realized.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic external view illustrating an exemplary externalconfiguration of an outdoor unit according to Embodiment 1 of thepresent invention.

FIG. 2 is a schematic perspective view illustrating an internalconfiguration of the outdoor unit according to Embodiment 1 of thepresent invention.

FIG. 3 is a schematic perspective view illustrating a configuration ofheat exchanger assemblies included in the outdoor unit according toEmbodiment 1 of the present invention.

FIG. 4 is a schematic perspective view illustrating a configuration ofknown heat exchanger assemblies.

FIG. 5 includes schematic perspective views each illustrating a part ofone of heat exchangers included in each of the heat exchanger assembliesincluded in the outdoor unit according to Embodiment 1 of the presentinvention.

FIG. 6 is a schematic perspective view illustrating a configuration ofheat exchanger assemblies included in an outdoor unit according toEmbodiment 2 of the present invention.

FIG. 7 is a circuit diagram schematically illustrating a basicconfiguration of an air-conditioning apparatus according to Embodiment 3of the present invention.

FIG. 8 is a schematic diagram illustrating some steps included in amethod of manufacturing a heat exchanger assembly according toEmbodiment 4 of the present invention.

FIG. 9 is a schematic diagram illustrating some other steps included inthe method of manufacturing a heat exchanger assembly according toEmbodiment 4 of the present invention.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will now be described withreference to the drawings.

Embodiment 1

FIG. 1 is a schematic external view illustrating an exemplary externalconfiguration of an outdoor unit 101 according to Embodiment 1 of thepresent invention. Referring to FIG. 1, an outline of the externalconfiguration of the outdoor unit 101 according to Embodiment 1 of thepresent invention will be described. In the drawings including FIG. 1 tobe referred to below, individual elements are not necessarily scaled inaccordance with their actual sizes.

The outdoor unit 101 according to Embodiment 1 forms a part of anindustrial-use air-conditioning apparatus used in, for example, anoffice building or a factory. The outdoor unit 101 has an appearance asillustrated in FIG. 1 and is configured to exhaust air from twopositions in an upper portion thereof. The outdoor unit 101 is connectedto a non-illustrated indoor unit, whereby an air-conditioning apparatusis provided. Devices (a compressor, a heat-source-side heat exchanger,an expansion device, and a use-side heat exchanger) included in theoutdoor unit 101 and the indoor unit are connected to one another bypipes, whereby a refrigeration cycle is formed, and air conditioning ofan air-conditioned space (for example, a room space or the like wherethe indoor unit is installed) is performed. The air-conditioningapparatus will be described in Embodiment 3.

The outdoor unit 101 includes at least a housing 102, heat exchangerassemblies 103, bell mouths 104, a cover 105, a non-illustratedcompressor, and non-illustrated pipe components. The outdoor unit 101has two fans (for example, propeller fans or the like corresponding to afan 55 to be mentioned in Embodiment 3) provided in the upper portion ofthe housing 102. The outdoor unit 101 takes in air from surfaces of thehousing 102 by an effect produced by the fans, allows the air to flowthrough the heat exchanger assemblies 103, and exhausts the air from theupper portion of the housing 102. In FIG. 1, the bell mouths 104 aresimplified as cylindrical members.

The housing 102 has a substantially rectangular parallelpiped shape andforms an outer shell of the outdoor unit 101. Some of the devicesforming the refrigeration cycle are housed by the housing 102. The heatexchanger assemblies 103 allow the air taken in by the fans and arefrigerant to exchange heat therebetween. The number of heat exchangerassemblies 103 is two in correspondence with the number of fans. Thebell mouths 104 guide the air that is made to flow by the fans providedin the upper portion of the housing 102. Two bell mouths 104 areprovided in correspondence with the number of fans.

The cover 105 is provided on one of the four surfaces of the housing 102(for example, a surface on which a control board is provided andmaintenance work and other kinds of work are performed by a worker, thatis, a surface illustrated on the near surface) and covers that surfaceof the housing 102. The other three surfaces of the housing 102 that arenot covered with the cover 105 allow the heat exchanger assemblies 103to be exposed to the peripheral environment in most part of the threesurfaces excluding portions provided with thin columnar or gratingmembers so that outside air can be taken into the heat exchangerassemblies 103. Although FIG. 1 illustrates an exemplary case where onesurface of the housing 102 is covered with one cover 105, the number ofcovers 105 is not specifically limited. One surface of the housing 102may alternatively be covered with a plurality of covers 105.

FIG. 2 is a schematic perspective view illustrating an internalconfiguration of the outdoor unit 101. Referring to FIG. 2, an outlineof the internal configuration of the outdoor unit 101 will be described.FIG. 2 schematically illustrates the internal configuration of theoutdoor unit 101 with members of the housing 102 excluding a bottomplate 119, and the devices provided in the housing 102 being removed soas to illustrate flows of the air produced in the outdoor unit 101.Hence, in FIG. 2, the bell mouths 104 appear to be spaced apart from thehousing 102. In addition, white arrows illustrated in FIG. 2 representthe flow of air produced by the effect of the fans, and the size of thewhite arrows corresponds to the wind speed.

The heat exchanger assemblies 103 each bent in a substantially U shapein a top view of the outdoor unit 101 are provided below the two bellmouths 104 in such a manner as to surround the two bell mouths 104,respectively. The heat exchanger assemblies 103 each include two layers.The two heat exchanger assemblies 103 are arranged symmetrically withrespect to a line connecting the longitudinal centers of the housing102. Hereinafter, one of the two heat exchangers that is on the outersurface in the outdoor unit 101 is referred to as outer heat exchanger106, and the other heat exchanger that is on the inner surface in theoutdoor unit 101 is referred to as inner heat exchanger 107. Sides ofthe two respective outer heat exchangers 106 that are adjacent to eachother are referred to as outer adjacent surfaces 108. Sides of the tworespective inner heat exchangers 107 that are adjacent to each other arereferred to as inner adjacent surfaces 109.

The outer heat exchangers 106 and the inner heat exchangers 107 eachinclude, for example, heat transfer tubes each having a flatcross-sectional shape (hereinafter referred to as flat tubes). The flattubes are fitted in plate-like fins that are arranged at predeterminedintervals. The plate-like fins each have fitting holes provided in theform of notches and in the same number and at the same intervals as theflat tubes in a plate-long-axis direction. Alternatively, the outer heatexchangers 106 and the inner heat exchangers 107 each include, forexample, heat transfer tubes each having a circular cross-sectionalshape (hereinafter referred to as circular tubes). The circular tubesare fitted in plate-like fins that are arranged at predeterminedintervals. The plate-like fins each have circular fitting holes providedin the same number and at the same intervals as the circular tubes inthe plate-long-axis direction. The configurations of the outer heatexchanger 106 and the inner heat exchanger 107 will be described indetail separately below, referring to FIG. 5.

The devices such as the compressor provided in the housing 102 aredisposed on the bottom plate 119 of the housing 102 in such a manner asto be surrounded from three surfaces by the heat exchanger assemblies103. The two heat exchanger assemblies 103 are arranged side by side andsymmetrically with respect to a gap 110 of a predetermined space andsuch that excessive spaces are not provided in the housing 102, withconsideration for the ease of assembling of the pipes projecting fromend surfaces 125 of the heat exchanger assemblies 103 (surfaces of theouter adjacent surfaces 108 and the inner adjacent surfaces 109 thatface the cover 105) and the space occupied (the space in the housing 102occupied by the heat exchanger assemblies 103).

That is, when the housing 102 is seen as a whole as illustrated in FIG.1, the two heat exchanger assemblies 103 are arranged such that two ofthe three surfaces of each heat exchanger assembly 103 excluding theadjacent surface (including the outer adjacent surfaces 108 and theinner adjacent surfaces 109) are positioned on corresponding ones of thethree surfaces of the housing 102 on which the heat exchanger assemblies103 are exposed. One of the two surfaces, excluding the adjacentsurface, of the heat exchanger assembly 103 on the left side in FIG. 2that is opposite the adjacent surface is denoted as surface 111, and theother that is opposite the cover 105 is denoted as surface 112.Likewise, one of the two surfaces, excluding the adjacent surface, ofthe heat exchanger assembly 103 on the right side in FIG. 2 that isopposite the adjacent surface is denoted as surface 114, and the otherthat is opposite the cover 105 is denoted as surface 113.

Note that a surface of the housing 102 that is opposite the cover 105allows the heat exchanger assemblies 103 to be exposed to the peripheralenvironment so that outside air can be taken into the heat exchangerassemblies 103. Therefore, air is also taken in from the outer adjacentsurfaces 108 and the inner adjacent surfaces 109.

The flow of air produced in the outdoor unit 101 configured as above isroughly illustrated in FIG. 2. Specifically, air having flowed into thehousing 102 from three surfaces of the housing 102 by the effect of thefans flows through the heat exchanger assemblies 103 and the bell mouths104 and is exhausted from the upper portion of the housing 102. In thisprocess, since the surfaces 111 to 114 of the heat exchanger assemblies103 each have a larger cross-sectional area of openings that face towardthe outside of the housing 102 than the adjacent surfaces of the heatexchanger assemblies 103, the draft resistance is smaller on thesurfaces 111 to 114, allowing the air to flow therethrough at a higherspeed. On the other hand, air is also taken in from the outer adjacentsurfaces 108 and the inner adjacent surfaces 109. However, since thecross-sectional area of openings in each of the outer adjacent surfaces108 and the inner adjacent surfaces 109 that face toward the outside ofthe housing 102 is small, the draft resistance is large on the outeradjacent surfaces 108 and the inner adjacent surfaces 109, limiting theair to flow therethrough at a lower speed.

FIG. 3 is a schematic perspective view illustrating the configuration ofthe heat exchanger assemblies 103. FIG. 4 is a schematic perspectiveview illustrating a configuration of a known heat exchanger assemblies(hereinafter denoted as heat exchanger assemblies 103′). Referring toFIGS. 3 and 4, the configuration of the heat exchanger assemblies 103will be described in comparison with the configuration of the heatexchanger assemblies 103′. Members included in the heat exchangerassemblies 103′ are denoted by corresponding reference numerals eachsuffixed with a prime (′) as a matter of convenience for ease ofcomparison with the corresponding members of the heat exchangerassemblies 103 included in the outdoor unit 101 according to Embodiment1.

The heat exchanger assemblies 103 are each ultimately bent in asubstantially U shape, as described above, in which the fins are stackedand the heat transfer tubes extending therethrough extend in a directionof a contour line 117. The heat exchanger assemblies 103 each includetwo layers: the outer heat exchanger 106 and the inner heat exchanger107. In the two heat exchanger assemblies 103, the outer adjacentsurfaces 108 of the two respective outer heat exchangers 106 and theinner adjacent surfaces 109 of the two respective inner heat exchangers107 face each other.

The outer heat exchangers 106 and the inner heat exchangers 107 includedin the heat exchanger assemblies 103 each include heat transfer tubes(flat tubes or circular tubes). The heat transfer tubes are fitted inplate-like fins that are arranged at predetermined intervals. Theplate-like fins each have fitting holes (encompassing notches) providedin the same number and at the same intervals as the heat transfer tubesin the plate-long-axis direction. The fins are formed as follows. Afterpressing is performed, a desired number of fins obtained by cutting andeach having a desired strip length are sequentially stacked in a collarsection. Subsequently, a plurality of long heat transfer tubes calledhair pins and each including a U-shaped portion 115 are inserted intothe fins.

The fins included in each of the outer heat exchanger 106 and the innerheat exchanger 107 are stacked at predetermined intervals and are fixed.That is, as illustrated in FIG. 3, the intervals between the finsincluded in each of the outer heat exchanger 106 and the inner heatexchanger 107 are changed in some portions. Subsequently, the pluralityof heat transfer tubes (flat tubes or circular tubes) are brazed toU-bends 116 for pipe connection each being bent in a U shape at an endof a corresponding one of the heat exchangers, and to other componentssuch as a distributor, whereby a continuous refrigerant passage that isfolded many times while passing through the fins is provided.Subsequently, the stack of fins in which the heat transfer tubes arefitted is bent into an L shape a plurality of times (twice, forexample), whereby the outer heat exchanger 106 and the inner heatexchanger 107 each ultimately have a substantially U shape in which thefins are stacked and the heat transfer tubes extending therethroughextend in the direction of the contour line 117.

Likewise, the heat exchanger assemblies 103′ are each bent in asubstantially U shape. Furthermore, the heat exchanger assemblies 103′each include two layers: an outer heat exchanger 106′ and an inner heatexchanger 107′. In the two heat exchanger assemblies 103′, outeradjacent surfaces 108′ of the two respective outer heat exchangers 106′and inner adjacent surfaces 109′ of the two respective inner heatexchangers 107′ face each other. As can be seen from the above, the heatexchanger assemblies 103 and the heat exchanger assemblies 103′ havesimilar appearances.

In general, the outer heat exchangers 106′ and the inner heat exchangers107′ included in the heat exchanger assemblies 103′ each includecircular tubes. The circular tubes are fitted in plate-like fins thatare arranged at predetermined intervals. The plate-like fins each havecircular fitting holes provided in the same number and at the sameintervals as the circular tubes in the plate-long-axis direction. Asdescribed in Background Art, the edges of the circular holes provided ineach of the fins are burred and thus form cylindrical collars so thatthe area of the fin that is in close contact with each of the heattransfer tubes is increased. Furthermore, flat portions of the finsbetween the circular holes have slits that improve the heatexchangeability with draft air. The fins are formed as follows. Afterpressing is performed, a desired number of fins obtained by cutting andeach having a desired strip length are sequentially stacked in a collarsection. Subsequently, a plurality of long circular tubes called hairpins and each including a U-shaped portion 115′ are inserted into thefins.

As described above, in forming the outer heat exchanger 106′ and theinner heat exchanger 107′, the stacking of the fins and the fitting ofthe circular tubes are performed with reference to the collars.Consequently, the fins included in the outer heat exchanger 106′ and theinner heat exchanger 107′ are stacked and fixed at regular intervalscorresponding to the height of the collars. That is, as illustrated inFIG. 4, the intervals between the fins included in each of the outerheat exchanger 106′ and the inner heat exchanger 107′ are constant.Subsequently, the plurality of circular tubes are brazed to U-bends 116′for pipe connection each being bent in a U shape at an end of acorresponding one of the heat exchangers, and to other components suchas a distributor, whereby a continuous refrigerant passage that isfolded many times while passing through the fins is provided.Subsequently, the stack of fins in which the circular tubes are fittedis bent into an L shape a plurality of times (twice, for example),whereby the outer heat exchanger 106′ and the inner heat exchanger 107′each ultimately have a substantially U shape in which the fins arestacked and the heat transfer tubes extending therethrough extend in thedirection of the contour line 117′.

The pitch of the fins included in the outer heat exchanger 106′ and theinner heat exchanger 107′ configured as above is determined to beconstant by the height of the collars formed by burring. Therefore, asdescribed in Background Art, it is difficult to change the fin pitch inaccordance with the internal configuration of the outdoor unit.

In contrast, unlike the known art, the fin pitch of the outer heatexchanger 106 and the inner heat exchanger 107 included in each of theheat exchanger assemblies 103 is readily changeable. That is, unlike theknown art, the outer heat exchanger 106 and the inner heat exchanger 107included in each of the heat exchanger assemblies 103 do not include fincollars, and the pitch of the fins is therefore not determined to beconstant by the height of the collars formed by burring. In anothercase, since fin collars that are shorter than the stacking intervalsbetween the fins are provided, the fin pitch is readily changeable. Inthe outdoor unit 101 according to Embodiment 1, since the fin pitch isreadily changeable, the fins can be arranged with consideration for theinternal configuration and the cost performance of the outdoor unit 101.Thus, the outdoor unit 101 according to Embodiment 1 can provideimproved heat exchanging efficiency and can save energy.

As illustrated in FIG. 2, since the surfaces 111 to 114 of the heatexchanger assemblies 103 each have a larger cross-sectional area ofopenings that face toward the outside of the housing 102 than theadjacent surfaces (the outer adjacent surfaces 108 and the inneradjacent surfaces 109) of the heat exchanger assemblies 103, the draftresistance is smaller on the surfaces 111 to 114, allowing the air toflow therethrough at a higher speed. That is, since the adjacentsurfaces of the heat exchanger assemblies 103 each have a smallcross-sectional area of openings that face toward the outside of thehousing 102, the draft resistance is large on the adjacent surfaces,limiting the air to flow therethrough at a low speed. Hence, in the heatexchanger assemblies 103, as illustrated in FIG. 3, the intervalsbetween the fins included in the outer adjacent surfaces 108 and theinner adjacent surfaces 109 are larger than the intervals between thefins included in the surfaces 111 to 114.

FIG. 5 includes schematic perspective views each illustrating a part ofone of the heat exchangers (the outer heat exchanger 106 and the innerheat exchanger 107) included in each of the heat exchanger assemblies103. Referring to FIG. 5, the configuration of the outer heat exchanger106 and the inner heat exchanger 107 will be described in detail. FIG.5( a) illustrates either of the outer heat exchanger 106 and the innerheat exchanger 107 that include flat tubes 1. FIG. 5( b) illustrateseither of the outer heat exchanger 106 and the inner heat exchanger 107that include circular tubes 1A. The outer heat exchanger 106 and theinner heat exchanger 107 that include the flat tubes 1 are generallyreferred to as flat-tube heat exchanger 120. The outer heat exchanger106 and the inner heat exchanger 107 that include the circular tubes 1Aare generally referred to as circular-tube heat exchanger 120A.

The outer heat exchanger 106 or the inner heat exchanger 107 illustratedin FIG. 5( a) includes flat heat transfer tubes each having across-sectional shape defined by a partially curved line. That is, theflat-tube heat exchanger 120 includes a plurality of flat tubes 1 eachhaving a flat cross section whose long sides are defined by straightlines and whose short sides are defined by curved lines each forming,for example, a semicircle or the like. The plurality of flat tubes 1 arearranged parallel to one another at predetermined intervals (regularintervals, for example) in a direction orthogonal to the direction ofthe passage of the refrigerant that is made to flow therethrough.

The flat-tube heat exchanger 120 further includes a plurality offlat-plate-like (rectangular) fins 2. The fins 2 are arranged parallelto one another at predetermined intervals in the direction of therefrigerant passage (a direction orthogonal to the direction in whichthe flat tubes 1 are arranged side by side). The fins 2 each have arectangular shape with a length in the long-axis direction of the flattubes 1 being larger than a length in the width direction of the flattubes 1 (the vertical direction in the drawing). Therefore, the widthdirection of the flat tubes 1 is defined as short-side direction, andthe long-axis direction of the flat tubes 1 is denoted as long-sidedirection.

The flat tubes 1 each have thereinside a plurality of holes 3 extendingside by side in the width direction. A refrigerant is made to flow inthe holes 3. The refrigerant exchanges heat with, for example, airflowing through the flat-tube heat exchanger 120. The fins 2 each have aplurality of notches 4 arranged in the long-side direction. The notches4 are provided in correspondence with the flat tubes 1. That is, forexample, the notches 4 are provided in the same number and at the sameintervals (excluding the ones at both ends) as the flat tubes 1.Furthermore, the notches 4 each have substantially the same width as theflat tubes 1. The notches 4 are provided such that one end of the fin 2is open. That is, the notches 4 are provided side by side in a comb-likepattern in the long-side direction of the fin 2.

The fin 2 further has gate-type (bridge-type) cut-raised portions 5provided by cutting and raising respective portions of the fin 2 betweenthe notches 4. The cut-raised portions 5 promote the heat exchangebetween air and the refrigerant. Furthermore, the fin 2 has fin collars6 provided by raising the edges of the notches 4 perpendicularly withrespect to the fin 2. The fin collars 6 provided by cutting and raisingthe fin 2 each have a shorter length than the stacking intervals betweenthe fins 2.

The plurality of flat tubes 1 are arranged side by side, and the notches4 of the fins 2 are fitted onto the thus arranged flat tubes 1.Subsequently, the flat tubes 1 and the fin collars 6 are joined to eachother with a brazing material or the like, whereby the flat tubes 1 andthe fins 2 are fixed to each other. Regarding the flat-tube heatexchanger 120 having such a configuration, many pieces of literatureshow that capacity performance that is higher than or equal to that of aknown heat exchanger including circular tubes and fins is providedbecause of several points such as an increase in the area of contactsurface between the refrigerant and each of the tubes having a reducedthickness. Furthermore, the size of the flat-tube heat exchanger 120 isselected in accordance with the performance required in the outdoor unit101, and such a flat-tube heat exchanger 120 is to be included in theoutdoor unit 101.

The outer heat exchanger 106 or the inner heat exchanger 107 illustratedin FIG. 5( b) includes the circular tubes 1A each having a partiallycircular cross-sectional shape. The plurality of circular tubes 1A arearranged in a checkered pattern at predetermined intervals (regularintervals, for example) in a direction orthogonal to the direction ofthe passage of the refrigerant that is made to flow therethrough. Thecircular-tube heat exchanger 120A further includes flat-plate-like fins2A that are similar to the fins 2 of the flat-tube heat exchanger 120.The fins 2A are arranged parallel to one another at predeterminedintervals in the direction of refrigerant passage (a directionorthogonal to the direction in which the circular tubes 1A are arrangedside by side).

A refrigerant is made to flow in the circular tubes 1A. The refrigerantexchanges heat with, for example, air flowing through the circular-tubeheat exchanger 120A. The fins 2A each have a plurality of notches 4A.The notches 4A are provided in correspondence with the circular tubes1A. That is, for example, the notches 4A are provided in the same numberand at the same intervals (excluding the ones at both ends) as thecircular tubes 1A.

Furthermore, the fins 2A each have gate-type (bridge-type) cut-raisedportions 5A provided by cutting and raising portions of the fin 2Abetween the notches 4A. The cut-raised portions 5A promote the heatexchange between air and the refrigerant. Furthermore, the fin 2A hasfin collars 6A provided by raising the edges of the notches 4Aperpendicularly with respect to the fin 2A. As with the fin collars 6,the fin collars 6A provided by cutting and raising the fin 2A each havea shorter length than the stacking intervals between the fins 2A.

The plurality of circular tubes 1A are arranged at predeterminedintervals, and the notches 4A of the fins 2A are fitted onto the thusarranged circular tubes 1A. Subsequently, the circular tubes 1A and thefin collars 6A are joined to each other with a brazing material or thelike, whereby the circular tubes 1A and the fins 2A are fixed to eachother. The size of the circular-tube heat exchanger 120A is selected inaccordance with the performance required in the outdoor unit 101, andsuch a circular-tube heat exchanger 120A is to be included in theoutdoor unit 101.

As described above, the outdoor unit 101 includes the heat exchangerassemblies 103 each including the flat-tube heat exchangers 120 or thecircular-tube heat exchangers 120A, and the fins in the outer adjacentsurfaces 108 and the inner adjacent surfaces 109 are stacked at a largerfin pitch than in the other surfaces 111 to 114, whereby the fins can bedistributed more effectively than in the known art. In the outdoor unit101, since the fins can be arranged at a density that is suitable forperformance improvement, the heat exchanging efficiency is improved fromthe viewpoint of cost performance. Thus, energy saving and costreduction are realized. Furthermore, if there is no problem withperformance specifications of the outdoor unit that are the same asthose in the known art, the performance improvement described above maybe translated into a reduction in the total number of fins, whereby thesize and the costs of the outdoor unit 101 can be reduced whilesubstantially the same level of performance is provided.

While the above description concerns an exemplary case where a pluralityof cut-raised portions 5 are provided between the notches 4 of each ofthe fins 2 so as to produce a more energy saving effect, the cut-raisedportions 5 are not necessarily provided. Likewise, while the abovedescription concerns another exemplary case where a plurality ofcut-raised portions 5A are provided between the notches 4A of each ofthe fins 2A so as to produce a more energy saving effect, the cut-raisedportions 5A are not necessarily provided.

Embodiment 2

FIG. 6 is a schematic perspective view illustrating a configuration ofheat exchanger assemblies 103A included in an outdoor unit according toEmbodiment 2 of the present invention. Referring to FIG. 6, theconfiguration of the heat exchanger assemblies 103A will now bedescribed. The configuration of the outdoor unit according to Embodiment2 is basically the same as that of the outdoor unit 101 described inEmbodiment 1. The description of Embodiment 2 focuses on differencesfrom Embodiment 1. Elements that are the same as those of Embodiment 1are denoted by corresponding reference numerals, and description thereofis omitted.

As with the heat exchanger assemblies 103 described in Embodiment 1, theheat exchanger assemblies 103A are each bent in a substantially U shapesuch that, ultimately, the fins are stacked and the heat transfer tubesextending therethrough extend in the direction of the contour line 117.The heat exchanger assemblies 103A each include two layers: an outerheat exchanger 106A and an inner heat exchanger 107A. In the two heatexchanger assemblies 103A, outer adjacent surfaces 108A of the tworespective outer heat exchangers 106A and inner adjacent surfaces 109Aof the two respective inner heat exchangers 107A face each other.

The outer heat exchangers 106A and the inner heat exchangers 107Aincluded in the heat exchanger assemblies 103A each include heattransfer tubes (flat tubes or circular tubes). The heat transfer tubesare fitted into plate-like fins that are arranged at predeterminedintervals. The plate-like fins each have fitting holes (encompassingnotches) provided in the same number and at the same intervals as theheat transfer tubes in the plate-long-axis direction. The fins areformed as follows. After pressing is performed, a desired number of finsobtained by cutting and each having a desired strip length aresequentially stacked in a collar section. Subsequently, a plurality oflong heat transfer tubes called hair pins and each including a U-shapedportion 115 are inserted into the fins.

The fins included in each of the outer heat exchanger 106A and the innerheat exchanger 107A are stacked at predetermined intervals and arefixed. Subsequently, the plurality of heat transfer tubes (flat tubes orcircular tubes) are brazed to U-bends 116 for pipe connection each beingbent in a U shape at an end of a corresponding one of the heatexchangers, and to other components such as a distributor, whereby acontinuous refrigerant passage that is folded many times while passingthrough the fins is provided. Subsequently, the stack of fins in whichthe heat transfer tubes are fitted is bent into an L shape a pluralityof times (twice, for example), whereby the outer heat exchanger 106A andthe inner heat exchanger 107A each ultimately have a substantially Ushape in which the fins are stacked and the heat transfer tubesextending therethrough extend in the direction of the contour line 117.

Unlike the known art, the fin pitch of the outer heat exchanger 106A andthe inner heat exchanger 107A included in each of the heat exchangerassemblies 103A is readily changeable. That is, unlike the known art,the pitch of the fins of the outer heat exchanger 106A and the innerheat exchanger 107A included in each of the heat exchanger assemblies103A is not determined to be constant by the height of collars formed byburring. In another case, fin collars that are shorter than the stackingintervals between the fins are provided. Therefore, the fin pitch isreadily changeable. Thus, the outer heat exchanger 106A and the innerheat exchanger 107A are configured with much consideration for thethickness of the fins and the stacking intervals between the fins.

As described in Embodiment 1, since the surfaces 111 to 114 of the heatexchanger assemblies 103A each have a larger cross-sectional area ofopenings that face toward the outside of the housing than the adjacentsurfaces (the outer adjacent surfaces 108A and the inner adjacentsurfaces 109A) of the heat exchanger assemblies 103A, the draftresistance is smaller on the surfaces 111 to 114, allowing the air toflow therethrough at a higher speed. That is, in the heat exchangerassemblies 103A, since the cross-sectional area of openings of theadjacent surfaces that face toward the outside of the housing is small,the draft resistance is large on the adjacent surfaces, limiting the airto flow therethrough at a low speed.

Hence, in the heat exchanger assemblies 103A, as illustrated in FIG. 6,the intervals between the fins included in the outer adjacent surfaces108A and the inner adjacent surfaces 109A are larger in some portionsthan the intervals between the fins included in the surfaces 111 to 114.That is, the stacking intervals between the fins in a surface 36 of eachouter adjacent surfaces 108A that is nearer to the end is larger thanthe stacking intervals between the fins in a surface 38 of the outeradjacent surfaces 108A that is nearer to the curved portion (bentportion). Thus, the heat exchanging efficiency can be improved in thoseportions nearer to the end portions of the outer adjacent surfaces 108Aand the inner adjacent surfaces 109A in each of which thecross-sectional area of openings that face toward the outside of thehousing is small.

The outdoor unit according to Embodiment 2 includes the heat exchangerassemblies 103A in which the fin pitch is readily changeable as in theheat exchanger assemblies 103 described in Embodiment 1. Hence, the finscan be arranged at a density that is suitable for performanceimprovement with further consideration for the internal configuration ofthe outdoor unit, and the fins can be arranged from the viewpoint ofcost performance. Thus, in the outdoor unit according to Embodiment 2,the heat exchanging efficiency is further improved, and further energysaving is realized. Moreover, if there is no problem with performancespecifications of the outdoor unit that are the same as those in theknown art, the performance improvement described above may be translatedinto a reduction in the total number of fins 2, whereby the size and thecosts of the outdoor unit 101 can be reduced while substantially thesame level of performance is provided.

Embodiment 3

FIG. 7 is a circuit diagram schematically illustrating a basicconfiguration of an air-conditioning apparatus 50 according toEmbodiment 3 of the present invention. Referring to FIG. 7, theconfiguration and operations of the air-conditioning apparatus 50 willnow be described. The air-conditioning apparatus 50 includes an outdoorunit and an indoor unit. A refrigerant is made to circulate throughdevices provided in the outdoor unit and the indoor unit, whereby acooling operation or a heating operation is realized. While Embodiment 3concerns a case where the air-conditioning apparatus 50 includes theoutdoor unit 101 according to Embodiment 1, the air-conditioningapparatus 50 may alternatively include the outdoor unit according toEmbodiment 2.

The air-conditioning apparatus 50 includes devices such as a compressor51, a heat-source-side heat exchanger 52, an expansion device 53, and ause-side heat exchanger 54 that are connected to one another by pipes.Among these devices, the compressor 51 and the heat-source-side heatexchanger 52 are included in the outdoor unit 101, and the expansiondevice 53 and the use-side heat exchanger 54 are included in an indoorunit 60. The expansion device 53 may be included in the outdoor unit101, not in the indoor unit 60. In addition, a non-illustrated flowswitching device such as a four-way valve configured to switch the flowof the refrigerant may be provided on a discharge side of the compressor51.

The compressor 51 sucks the refrigerant and compresses the refrigerant,whereby the refrigerant becomes a high-temperature and high-pressurestate. The compressor 51 is, for example, an inverter compressor or thelike whose capacity is controllable. The heat-source-side heat exchanger52 allows the refrigerant and air that is forcibly supplied thereto froma fan 55 to exchange heat therebetween. The heat exchanger assembliesdescribed in Embodiment 1 or Embodiment 2 are employed as theheat-source-side heat exchanger 52. The expansion device 53 expands therefrigerant by reducing the pressure of the refrigerant and includes,for example, an electronic expansion valve or the like whose openingdegree is variably controllable. The use-side heat exchanger 54 allowsthe refrigerant and air that is forcibly supplied thereto from anon-illustrated air-sending device such as a fan to exchange heattherebetween. The fan 55 includes fans provided in the same number asthe heat exchanger assemblies included in the heat-source-side heatexchanger 52. The fan 55 supplies air to the heat-source-side heatexchanger 52.

The heating operation and the cooling operation performed by theair-conditioning apparatus 50 will now be described briefly.

[Heating Operation]

When the compressor 51 is driven, the compressor 51 raises the pressureof the refrigerant, whereby the refrigerant becomes a high-temperatureand high-pressure state and is discharged. The refrigerant dischargedfrom the compressor 51 is supplied to the use-side heat exchanger 54 andis cooled while exchanging heat with air, whereby the refrigerantbecomes a low-temperature and high-pressure state. In this step, heatingair is supplied from the indoor unit 60, whereby an air-conditionedspace is heated. The refrigerant is then discharged from the use-sideheat exchanger 54, undergoes pressure reduction by being expanded by theexpansion device 53, and becomes a low-temperature and low-pressurestate. The refrigerant is then heated in the heat-source-side heatexchanger 52 and flows into the compressor 51 again.

[Cooling Operation]

When the compressor 51 is driven, the compressor 51 raises the pressureof the refrigerant, whereby the refrigerant becomes a high-temperatureand high-pressure state and is discharged. The refrigerant dischargedfrom the compressor 51 is supplied to the heat-source-side heatexchanger 52 and is cooled while exchanging heat with air, whereby therefrigerant becomes a low-temperature and high-pressure state. Therefrigerant is then discharged from the heat-source-side heat exchanger52, undergoes pressure reduction by being expanded by the expansiondevice 53, and becomes a low-temperature and low-pressure state. Therefrigerant is then heated in the use-side heat exchanger 54. In thisstep, cooling air is supplied from the indoor unit 60, whereby theair-conditioned space is cooled. The refrigerant discharged from theuse-side heat exchanger 54 flows into the compressor 51 again.

As described above, the air-conditioning apparatus 50 includes theoutdoor unit 101 including the heat exchanger assemblies 103 eachincluding the flat-tube heat exchangers 120 or the circular-tube heatexchangers 120A. Accordingly, while the total number of fins 2 is notchanged, the fins 2 are stacked at a larger fin pitch in each of theouter adjacent surfaces 108 and the inner adjacent surfaces 109 than ineach of the other surfaces 111 to 114. Therefore, the fins 2 can bedistributed more effectively than in the known art. In theair-conditioning apparatus 50, since the fins can be arranged at adensity that is suitable for performance improvement, the heatexchanging efficiency is improved from the viewpoint of costperformance. Thus, energy saving and cost reduction are realized.

Embodiment 4

FIG. 8 is a schematic diagram illustrating some steps included in amethod of manufacturing a heat exchanger assembly according toEmbodiment 4 of the present invention. Referring to FIG. 8, a method ofmanufacturing a flat-tube heat exchanger included in the heat exchangerassembly 103 will now be described. Herein, a case where the flat-tubeheat exchanger 120 described in Embodiment 1 is manufactured will bedescribed. In Embodiment 4, elements that are the same as those of anyof Embodiments 1 to 3 are denoted by corresponding reference numerals,and description thereof is omitted.

First, a coil of, for example, aluminum thin plate that is to becomefins 2 is prepared. Subsequently, the aluminum thin plate that is fedfrom the coil is pressed by using a non-illustrated progressive dieplaced on a high-speed pressing machine. Then, notches 4 areconsecutively press-formed in the aluminum thin plate together withcircular pilot holes 16 that are formed at both outer-side ends of thealuminum thin plate. In this step, an intermittent hoop feedingoperation (arrow 17) is performed by utilizing positioning pins that arefitted into the pilot holes 16. In this manner, the aluminum thin plateis fed as a series of fins 18 in a hoop state as illustrated in FIG. 8.

The series of fins 18 is cut into individual fins 2 by a cuttingoperation (arrow 19) performed by a cutter above a plurality of flattubes 1 that are arranged side by side. Subsequently, each of the fins 2is held by a non-illustrated transfer mechanism including, for example,a cam and a servo, and is lowered in a moving and rotating operation(arrow 20). In this manner, the fins 2 are fitted onto the flat tubes 1from an open side of the notches 4. Lastly, the fins 2 are pressed downonto the flat tubes 1 such that each of the fins 2 is at a predeterminedinterval from the last one in a group of fins 21 that have already beenfitted onto the flat tubes 1 and until the rear edges of the notches 4come into contact with the tops of the flat tubes 1. Thus, fitting andpositioning of the fins 2 performed on the flat tubes 1 are complete.

On the other hand, the flat tubes 1 are placed on a non-illustratedtransporting mechanism (a hoop feeding mechanism, for example)including, for example, a servo, a ball screw, a linear guide, and soforth so that the plurality of flat tubes 1 arranged side by side can bemoved and positioned altogether in the long-axis direction. Then, theflat tubes 1 are positioned in the long-axis direction of the flat tubes1 in a pitch feeding operation (arrow 22) performed by the transportingmechanism. The pitch feeding operation is performed such that apredetermined interval from the last fin in the group of fins 21 thathave already been fitted onto the flat tubes 1 is provided.

The cutting operation (arrow 19) and the moving and rotating operation(arrow 20) performed on the fins 2 and the pitch feeding operation(arrow 22) performed on the flat tubes 1 are executed in that orderfollowing the hoop feeding operation (arrow 17) performed by thehigh-speed press and in synchronization with the operations performed bythe transfer mechanism and the servo mechanism. Consequently, the fins 2are stacked at predetermined intervals. Any lags in the synchronizationbetween the high-speed press and the transfer mechanism may be absorbedby, for example, giving some slack in the hoop around transport rollersin such a manner as to provide a buffer for the hoop, and by increasingor decreasing the pressing stroke while detecting the amount of slack.

Furthermore, the fin pitch is adjustable to a desired value by changingthe length of pitch feeding in the pitch feeding operation (arrow 22).The length of pitch feeding is adjusted in accordance with a setting ona controller that controls the transporting mechanism. A large length ofpitch feeding is set for a group of fins (a group of fins 23 illustratedin FIG. 8) that is to form the outer adjacent surfaces 108 or the inneradjacent surfaces 109 in which the wind speed is low. A small length ofpitch feeding is set for a group of fins (a group of fins 24 illustratedin FIG. 8) that is to form any of the surfaces 111 to 114. In thismanner, a required number of fins 2 are stacked. Thus, a fin groupassembly 25 including the group of fins 23 that are stacked at largeintervals and the fins 24 that are stacked at small intervals isobtained. Note that FIG. 8 illustrates a state where the fin groupassembly 25 has been assembled halfway.

The fin group assembly 25 obtained by completing the stacking of thefins 2 is fixed to the flat tubes 1 by brazing in a furnace with abrazing material that has coated over the flat tubes 1 in advance or bybonding with a bonding agent applied in the gaps. Subsequently, two fingroup assemblies 25 are stacked, and the stack of the two fin groupassembly 25 is connected to pipe components and is folded into an Lshape twice, whereby assembling of the flat-tube heat exchanger 120having a substantially U shape is complete (see FIG. 9).

The flat-tube heat exchanger 120 is manufactured by the abovemanufacturing method. Therefore, unlike the known method in whichcircular tubes are inserted into a group of fins that have been stackedin advance, the stacking intervals are quickly changeable to any ofdifferent fin pitches (stacking intervals between the fins) simply bychanging a command value of the controller regarding the length of pitchfeeding that is set for the transporting mechanism, without using anycomplicated dies for changing the height of collars and any largepressing machines. That is, the manufacturing method according toEmbodiment 4 facilitates the change of the stacking pitch of the fins 2without increasing the cost of the die for the fins 2, the cost of thepressing machine, and troublesome assembling work.

Furthermore, unlike the known art in which the collars are short and thefins are not stacked with reference to the collars, the flat-tube heatexchanger 120 is configured such that a desired number of fins 2 can befitted onto the flat tubes 1 without moving the fins over the entirelength of the heat transfer tubes and regardless of the length of theflat tubes 1. Therefore, the flat-tube heat exchanger 120 is hardlyaffected by the shapes of workpieces. Hence, an operation that is quickenough to follow the speed, at several hundred SPM (strokes per minute),of punching performed by the high-speed pressing machine is realizedreadily. Furthermore, different fin pitches are realized.

FIG. 9 is a schematic diagram illustrating some other steps included inthe method of manufacturing a heat exchanger assembly according toEmbodiment 4 of the present invention. Referring to FIG. 9, a method ofmanufacturing the heat exchanger assembly 103A described in Embodiment 2will now be described. Note that FIG. 9 illustrates bending steps thatare subsequent to the steps of manufacturing the flat-tube heatexchanger 120 illustrated in FIG. 8.

A heat exchanger bending device 150 illustrated in FIG. 9 is for bendinga set of fin group assemblies 25 and includes at least an L-bending jig40 and a table 41. The L-bending jig 40 bends the flat tubes 1 includedin the set of fin group assemblies 25 substantially perpendicularly(into a substantially L shape). Specifically, the L-bending jig 40includes a holding portion 40 a that holds the set of fin groupassemblies 25 and a moving portion 40 b that rotates the holding portion40 a substantially perpendicularly. The holding portion 40 a that isholding a predetermined position of the set of fin group assemblies 25is rotated by the moving portion 40 b, whereby the flat tubes 1 arebent. In this step, the flat tubes 1 are bent substantiallyperpendicularly in the width direction.

The set of fin group assemblies 25 is placed on the table 41 and is slidin a predetermined direction (toward right in FIG. 9) by anon-illustrated driving unit such as rollers. The table 41 includes, forexample, a non-illustrated guide rail. When the guide rail is driven bythe driving unit, the set of fin group assemblies 25 placed on the table41 is slid.

As illustrated in FIG. 8, each fin group assembly 25 obtained bycompleting the stacking of the fins 2 is fixed to the flat tubes 1. Twofin group assemblies 25 are stacked and are connected to pipe components(for example, the U-shaped portions 115, the U-bends 116, and so forth).In this state, the set of fin group assemblies 25 is placed on the table41 of the heat exchanger bending device 150. The set of fin groupassemblies 25 placed on the table 41 is slid by the table 41. When theset of fin group assemblies 25 is slid to a predetermined position (theposition having the groups of fins 24 that are to form the outeradjacent surfaces 108 and the inner adjacent surfaces 109), the set offin group assemblies 25 is held by the holding portion 40 a of theL-bending jig 40. In this step, the holding portion 40 a holds thegroups of fins 24 in which the stacking intervals are small.

The set of fin group assemblies 25 held by the holding portion 40 a isbent, while being slid, substantially perpendicularly by the holdingportion 40 a that is rotated by the moving portion 40 b (firstL-bending). Thus, the set of fin group assemblies 25 has a first curvedportion 44. After the first curved portion 44 is formed, the holdingportion 40 a releases the set of fin group assemblies 25. The set of fingroup assemblies 25 is further slid in the forward direction by thetable 41. When the set of fin group assemblies 25 is slid to apredetermined position (the position having the groups of fins 24 thatare to form the surface 112 or the surface 113), the set of fin groupassemblies 25 is held by the holding portion 40 a of the L-bending jig40 again. In this step also, the holding portion 40 a holds the groupsof fins 24 in which the stacking intervals are small.

The set of fin group assemblies 25 held by the holding portion 40 a isbent, while being slid, substantially perpendicularly by the holdingportion 40 a that is rotated by the moving portion 40 b (secondL-bending). Thus, the set of fin group assemblies 25 has a second curvedportion 45. After the second curved portion 45 is formed, the holdingportion 40 a releases the set of fin group assemblies 25. In thismanner, the heat exchanger assembly 103A having a substantially U shapeis obtained.

As described above, since the heat exchanger bending device 150 holdsthe groups of fins 24 in which the stacking intervals are small by usingthe holding portion 40 a, the stress applied to the end surfaces of thefins 2 when the flat tubes 1 are bent is reduced. Therefore, in the heatexchanger bending device 150, the occurrence of tilting or buckling ofthe fins 2 in the bending step is suppressed efficiently. Hence, even ifthe fins 2 are relatively thin or the stacking intervals between thefins 2 are relatively large, the fins 2 can be arranged at largestacking intervals while a certain level of manufacturing quality ismaintained. Accordingly, in the method of manufacturing a heat exchangerassembly according to Embodiment 4, the heat exchanging efficiency isimproved from the viewpoint of cost performance, and a heat exchangerassembly in which energy saving, cost reduction, and size reduction arerealized is provided.

While Embodiment 4 concerns an exemplary method of manufacturing theheat exchanger assembly 103A described in Embodiment 2, Embodiment 4 maybe applied to a method of manufacturing the heat exchanger assembly 103described in Embodiment 1, needless to mention. In that case, however,the position to be held by the holding portion 40 a needs to bedetermined carefully.

While each of Embodiments concerns an exemplary case where portions ofthe flat tubes 1 extending in the adjacent surfaces (the outer adjacentsurfaces 108 and the inner adjacent surfaces 109) are shorter than theother portions of the flat tubes 1 extending in the surfaces excludingthe adjacent surfaces, the present invention is not limited thereto.Needless to mention, similar effects are expected to be produced even ifthe former portions of the flat tubes 1 have the same length as or arelonger than the portions of the flat tubes 1 extending in the surfacesexcluding the adjacent surfaces.

While each of Embodiments concerns an exemplary case where the outdoorunit includes two substantially U-shaped heat exchangers that arearranged side by side, similar effects are expected to be produced evenif the outdoor unit includes three or more heat exchangers, needless tomention, as long as the heat exchangers each have a surface that isadjacent to a surface of another heat exchanger. Furthermore, while nospecial description is given regarding the number of rows of heatexchangers that are stacked vertically in each of Embodiments, the heatexchanger may include one row as described in each of Embodiments, orthe heat exchanger may include two or more rows. Furthermore, while eachof Embodiments concerns an exemplary case where the heat exchangerincludes two layers, the present invention is not limited thereto.Similar effects are expected to be produced even with a heat exchangerincluding one layer or with a heat exchanger including three or morelayers.

REFERENCE SIGNS LIST

flat tube 1A circular tube 2 fin 2A fin 3 hole 4 notch 4A notch 5cut-raised portion 5A cut-raised portion 6 fin collar 6A fin collar 16pilot hole 17 arrow 18 series of fins 19 arrow 20 arrow 21 group of fins22 arrow 23 group of fins 24 group of fins 25 fin group assembly 36surface nearer to end 38 surface nearer to curved portion 40 L-bendingjig 40 a holding portion 40 b moving portion 41 table 44 first curvedportion 45 second curved portion 50 air-conditioning apparatus 51compressor 52 heat-source-side heat exchanger 53 expansion device 54use-side heat exchanger 55 fan 60 indoor unit 101 outdoor unit 102housing 103 heat exchanger assembly 103A heat exchanger assembly 104bell mouth 105 cover 106 outer heat exchanger 106A outer heat exchanger107 inner heat exchanger 107A inner heat exchanger 108 outer adjacentsurface 108A outer adjacent surface 109 inner adjacent surface 109Ainner adjacent surface 110 gap 111 surface 112 surface 113 surface 114surface 115 U-shaped portion 116 U-bend 117 contour line 119 bottomplate 120 flat-tube heat exchanger 120A circular-tube heat exchanger 125end surface 150 heat exchanger bending device

1. An outdoor unit comprising: a housing; at least two plate fin-tubeheat exchanger assemblies arranged side by side in the housing and eachbeing bent in an inward direction of the housing such that the heatexchanger assembly has a facing surface that faces a surface of anotherheat exchanger assembly in the housing; and a fan provided above thehousing and causes air taken in from surfaces of the housing to beexhausted from an upper portion of the housing, wherein each of the heatexchanger assemblies includes fins each having notches provided withoutfin collars or notches provided with fin collars that are shorter thanstacking intervals between the fins, and wherein at least some of thestacking intervals between the fins in a portion forming the facingsurface are larger than the stacking intervals between the fins inportions forming surfaces excluding the facing surface.
 2. The outdoorunit of claim 1, wherein, in a case where the heat exchanger assembliesare each bent substantially perpendicularly at least once, the stackingintervals between the fins in a portion of the facing surface that isnearer to an end are larger than the stacking intervals between the finsin another portion of the facing surface that is nearer to a bentportion.
 3. The outdoor unit of claim 2, wherein each of the heatexchanger assemblies is bent along surfaces of the housing excluding onesurface.
 4. The outdoor unit of claim 1, wherein each of the heatexchanger assemblies includes flat tubes each having a flatcross-sectional shape are fitted in the notches provided in the fins,the flat cross-sectional shape being a shape in which long side thereofis linear while short side thereof is curved in a semicircular manner.5. The outdoor unit of claim 4, wherein the fins each include aplurality of bridge-type cut-raised portions provided between thenotches.
 6. The outdoor unit of claim 4, wherein the fins are fixed tothe flat tubes, which are fitted in the notches, by brazing or bonding.7. An air-conditioning apparatus comprising: the outdoor unit of claim1; and an indoor unit connected to the outdoor unit.
 8. A method formanufacturing an outdoor unit including at least two fin-tube heatexchanger assemblies each being bent and having a facing surface thatfaces a surface of another heat exchanger assembly, the methodcomprising the steps of: in each of the at least two fin-tube heatexchanger assemblies, fitting fins onto a plurality of flat tubes froman open side of notches, the plurality of flat tubes being arranged sideby side and capable of moving and positioning altogether in a long-axisdirection, the fitting fins each having notches provided without fincollars or notches provided with fin collars that are shorter thanstacking intervals between the fins; adjusting at least some of thestacking intervals between the fins in a portion forming the facingsurface so as to have larger stacking intervals than the stackingintervals between the fins in portions forming surfaces excluding thefacing surface; and assembling the at least two fin-tube heat exchangerassemblies by bending thereof.